Trying to make a one-size-fits-all IC TV tuner for the world TV market is a real challenge. There are at least half a dozen different digital TV standards around the world, as well as some lingering analog standards. This makes the demodulator part of the design a complex multipart circuit. In the real world, that translates into different chips for each standard. One good way to overcome this problem is to use a software DSP demodulation approach. All you need is a processor with enough power to run the software, which is the approach taken by Mirics Semiconductor and its FlexiTV system.

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A few years ago, Mirics announced its FlexiTuner, which suits virtually any radio or TV standard. It is a classic front end with RF amps, mixer, PLL synthesizer, and IF filtering. The Mirics MSi001 and MSi002 cover all frequencies from 150 kHz through 1.9 GHz, making them candidates for any radio or TV product. The chips support zero-IF or low-IF formats and provide the I and Q outputs to any demodulator. The control interface is either I²C (MSi001) or serial peripheral interface (MSi002).

The missing piece of the receiver is the demodulation. Now, Mirics supplies the software that will demodulate virtually any TV standard. These include DVB-T, ISDB-T, DTMB, ATSC, DVB-H, CMMB (China), and T-DMB. It also supports analog TV (PAL, NTSC) and standard AM and FM analog as well as DAB, DRM, and HD Radio digital formats. This software is designed to run on a host processor like that inside any PC, laptop, or netbook.

The FlexiTV receiver employs the MSi3101 SmartTuner, which is a new version of the Mirics FlexiTuner. FlexiTV also includes the regular FlexiTuner plus a USB 2.0 digital interface. This combination can plug into any available USB port, making the computer a TV set (see figure below). With a BOM of less than $5, a Mirics-based TV receiver may have the lowest cost in the world.

The FlexiTV has become the world’s first broadcast TV receiver using software demodulation to comply with the latest NorDig 2.0 (Norway, Finland, Sweden, Denmark, Iceland) standard specification for digital terrestrial TV reception. The NorDig test specifications ensure that compliant quality products are developed for robust DVB-T reception. The NorDig 2.0 standard requires very modest system resources.

For example, a FlexiTV enabled notebook can receive live standard-definition DVB-T signals with just 30% CPU load. However, it is the move toward reception of HD signals that is really driving CPU resource requirements, where H.264 decoding presents a significantly greater burden than requirements for software demodulation. Mirics FlexiTV can comfortably accommodate the most demanding case of HD H.264 DVB-T reception with the resources of an entry-level dual-core x86-based PC.

This USB module is a complete TV receiver for use with PCs, laptops, and netbooks. It includes the Mirics FlexiTuner and a USB interface that work with demodulation/decoding software that runs on the computer CPU.

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